Uni-layer rigid airplane wing



UNI-LAYER RIGID AIRPLANE WiNG Filed July 9, 1929 INVENIOR, Jae wk ZZondZ 72,;

TTORNEY V 30 scope,lprinciple and. spirit of the: invention s H tunnel'tests and progressinthe art of dc.-

Patented May 12, 1931 JOSEPH BLONDIN, on LOS ANGELES, CALIFORNIA UNI-LAYER RIGID AIRPLANE WING Application filed- July 93929. Serial No; 376,917.

and to control surfaces for. airplanes. t

An object istoprovide features which will be superior in. pQlIlt;Qfsimplicity, low cost,

5 rigidity,durability, safety and'general serv-c iceability. c L v More particularly anobject is .to provide ,a substantial and. practicable" uni-layer; or monoply-body supporting surface as distinguished, fromia'll forms loflairplane wing and control planes embodying more than one ply in. the. body, Vwhether laminated or inter-. stitial. In this connection it is, furtlier,,an object to provide an unilayer surface, (used in the aeronautical sense) which is inherently rigid andcapableof holding, normally, its shaped form.fy

A further and: predominant Object of the present concept is tofiprovide. a supporting surface designed toproduce peculiar and advantageous air-flow-reactions on its lower and its upper faces, 7 0 her objects, advantages and featuresfof construction, combination and detail members and certain characteristics will be-made manifest in theensuingdescription of the herewithv illustrative embodiment it being understood that modifications, variationsrand adaptations. may be resorted to within the asfit ismore directly claimed hereinafteni V Figure, 1 is a top planof'the. improved wing orsurface. v 1

Figure 2 is a bottomplan. thereof Figure?) is across-section. 4

The wing'proper consistsof a single structural sheet 2 of any approved, "inherently rigid material which may be stamped, bent, cast or out to and will normallyretain its 4 desired or given curvature; i. e., will hold its shape prior to attachmentor incorporation of certain wing-bars, and ribs. i y

To the ventral, ,concaved face A, which re; acts to sustain, a load, in flight, there .is at:

taohed a, series. of generally p'arallelf wing bars, or beams 23, lengthwise of the wingfand in any preferred lateral spacedrelation' to each other. These are thin vertically; and of"streamlin e' design. I

A; plurality off ribs .isfapplied'dorsally and transversely to the top, of thewing in any desired mutual] spaced order.

a The advantages and superiority with ref erence toprior practice in airplane wing con: struction is that by utilizing an inherently 5 rigid surface this precludes the many qualities of deficiency concomitant,- with all forms ofv fabric and relatively flexible or pliantlmaterial of-any kind and differentiates the in: ventionjfrom early type single-surface fabric wings which anticipate this invention in appearanceonlyand whose very lack of the qualities and features this inventionfbrings to the art of wing construction resulted in their early abandonment in favor of the double-surfaced: wings universally used at this period. v i I Single-surface fabric covering stretched between or stretched over the ribs in early type vairplanewings were characterized by 7 the following defects: The covering was' so fiexibleand subject to extension andsagging, under air pressure,'as to present and maintain a very inefficient and constantly varyingv aerodyn amic curve to the air, resulting in comparatively poor lifting quality;the flexi: bility'and give of the fabric precluded theaoquisition ofany aerodynamic data to govern the study and development of wing-curves and their relative characteristics. Windsigning wing curves dates only from thetinle single-surface textile wing-covering was abandoned in, favor of 'double-surfaced,

wings. H urther, the. flexible single-surface wingcovering lent no factor of, strengthto the wing structure proper, in fact the necessity of lacing and stretching said surfaces to the ribs 1 and towing-spars. introduced added stresses tending to weaken the ribs and spars; also, the fabric covering was placed overthe ribsfor th'e'ribs' extended in depth, as much below as above the fabric cover and this robbed the wing, per se, off a valuablenot to saw fundamental feature of levitation C21 pab'le of'beingderived fr'cmjplay or action 'of air-current above and over a win and which actionv was little understood, therefore igacredyin the design-of suchv early-type mo faces respectively. The faster the flow of air over a wing and the slower,relatively, under the wing at the same and equal periods of time, the greater will be the suction over the surface andthe greater will be the lift furnished by the wing. Non-technically stated, a wing functions as follows; Upon propulsion its under, concave face impinges against, slows up and even carries along the air it encounters in its line of flight, whereas its upper, convex face at the same time recedes from, and accelerates theair fromsaid top face. The most eificient lifting wing will be one, which is designed to effect the maximum acceleration of the air fiow over its upper face and a maximum retardation of the air flow under its lower face during an equal lapse of time. v,

It is this application of aerodynamic law that explains the curve path of a spit-ball thrown by 'a base-ball pitcher,the sustention of a ball in a jet of water against the pull of gravity and the whole art of aviation by means of airplanes.

(This elucidation of the action of air currents upon and around the wing in travel is technically known as Prandtls boundary layer theory in aerodynamics; and in ballisties as the Magnus effect) The art of wing design, therefore, rapidly took the form of double-surface covering whose top and bottom face curvatures could be more positively maintained and studied,

and whose structuralelements or frame work could be contained between coverings and withdrawn from head-on and frictional resistance against the air. Experience soon developed the fact that this type of wing was more efficient the more rigidly it was constructed, which led, finally, to the introduction of abnormally thick wings, permitting great latitude in design of strong, rigid, wing spars so generally adopted today. The overall efficiency of these thick wings is relatively high due, not to the thickness itself which is a harmful factor involving the displacement of an equal bulk of air and abjsorbing much power in the effort, but more certainly to the rigidity of the element and to the greater difference of relative curvatures, made possible by the thickness: the differences favoring the formation of Prandtl vortices. 7

With these general principles in mind I deslr to particularly call attention to, the

fact that the instant invention involves a design of wing wherein: great rigidity is obtained by the choice of a stiff-body material produced, by appropriate mode, to a selected curve of known aerodynamic characteristics and capable of maintaining such curve independently of extraneous constructional elements: The choice of material, rigid in itself, will permit a more thorough and searching study of aerocurve characteristics and lead to the production of maximum efficiency in wing design: The rigid, mono-layer wing of determined, constant, arcuate shape becomes, in itself, a solid, minimum depth, integral-body wing-spar cooperating with the associated spar elements proper of the structural frame and lendin strength and resistance tobending along its length and with the frame of ribs and spars lending resistance to drag and torsional stresses as well: Unlike single-layer fabric wings, this invention discloses the application of the ribs to the upper face ofthe mono-layer, rigid body exclusively designed for the purpose of forming transverse ridges which constrain the air to flow in channels therebetween and directly across the wing in the shortest possible path along the line of flight.

On the other hand the set of wing-spars extending longitudinally of and under the wing sheet effect a slowing up of the air-flow by direct resistance and diverting said flow laterally outward towards the wing tips thus making the air-flow take a resultant, diagonal path as long and as retarded as possible under the wing. These wing-spars are not, of course, designed for direct head resistance but areproperly stream-lined and'do not add as much resistance to propulsion as do the thick, double surfaced wings of conventional airplanes in the displacement of their equivalent bulk of air. The wing-spars are to be distinguished from and contrasted with the conventional practice of using only two (front and rear) wing-spars because this inset out in my Patent #1,240,812, of Sept.

25, 1917 which form alone of all known types favors use of front and rear and intermediate spars by providing a support therefor on the stringer of the window-frame.

The thin, rigid,single-layer wing of this inventionaffords maximum 'efliciency as an aerodynamic surface and is stronger, simpler, cheaper and easier to handle in the set-up and knock-down of a machine than any other type ofequal surfacedesigned to date and possesses'the vitally important advantage of insurlng safety since it exposes at all times every element of construction of the complete wing. This feature, particularly, provides the possibility of constructin Y ideal seaplane w ngs free from rapid eterioration In contrast to the concealed condition of i all interior parts and surfaces of hollow wings the present wing body can be freely inspected at all times, When not in actual flight, without necessitating dismounting or manipulation of any parts, and those defective in any degree may be discovered and repaired or replaced with little loss of time because of accessibility and visibility.

As examples of appropriate stiff-body material for the supporting surface may be mentioned sheet-metal, bakelite, fibre and plywood.

What is claimed is:

1. A11 airplane supporting surface consisting of a thin, single layer, solid body of rigid, spar-forming character and having a series of longitudinal, ventral spars exposed to air-flow and forming longitudinal channels endwise of the surface.

2. An airplane supporting surface consistin of a thin, single-layer, solid body of spar-forming character, and a plurality of ribs fixed dorsally on the body-surface and forming ridges and channels from front to rear for determination of air-flow currents.

3. In airplane wing construction, a'thin, rigid, single-layer supporting surface whose top face is convex and has conforming, foreand-a-ft ribs, and whose lower face has 1on gitudinal wing-spars; said ribs and spars being exposed to constrain air-flow in differential channels alongthe top and the bottom faces of the surface.

4:. An airplane wing whose body is of solid, uni-layer, rigid form and has top ribs and bottom longitudinal spars, and whose air channels from front to rear on its top' surface and co-extensive therewith, and Whose bottom presents unobstructed, long1-' tudinal, air channels from end to end, and whose structural entirety is fully exposed for ready inspection and repair.

' JOSEPH BLONDIN. v 

